Method of using heat and tear sealing dies



Feb. 21, 1967 M. RAFFAELLI, SR 3,305,421

METHOD OF USING HEAT AND TEAR SEALING DIES Original Filed May 21, 1952 4Sheets-Sheet 1 fi V 744 M I w 4 A TTORNEY Feb. 21, 1967 M. L. RAFFAELLI,SR 3,305,421

METHOD OF USING HEAT AND TEAR SEALING DIES Original Filed May 21, 1962 4Sheets-Sheet 2 I I :m in

\ INVENTOR /v/za 4 ew wzzz/ \sae ATTORNEY Feb. 21, 1967 M. L. RAFFAELLI,SR 3,30

METHOD OF USING HEAT AND TEAR SEALING DIES 4 Sh ets-Sheet 3 OriginalFiled May 21 fig.

INVENTOK /'7/40 z. @4/727624/ ale 1967 M. L. RAFFAELLI, SR 3,305,421

METHOD OF USING HEAT AND TEAR SEALING DIES Original Filed May 21, 1962 4Sheets-Sheet 4 ff i 10 ATTOR NEY 3,305,421 METHOD OF USING HEAT AND TEARSEALING DIES Milo L. Rattaelli, Sr., Chicago, Ill., assignor to TheScholl Mfg. Co., Inc, Chicago, Ill., a corporation of New York Uriginalapplication May 21, W62, Ser. No. 196,228, now

Patent No. 3,244,573, dated Apr. 5, 1966. Divided and this applicationMay 5, H65, Ser. No. 453,326

5 Claims. (Cl. l56223) This application is a division of my copendingapplication entitled, Heat and Tear Sealing Dies and Method of Using theSame, filed May '21, 1962, Serial No. 196,228, now Patent No. 3,244,573.

This invention relates to improvements in a method of using heat andtear sealing dies, the dies being of the electrode type for electronichigh frequency heat sealing, and particularly desirable for use withplastic sheet and foam materials, effecting both a fine edge heat sealseam and at the same time providing a tear line immediately adjacent theseam for the easy removal of waste stock from the finished product, themethod of use being highly suitable in connection with the commercialmanufacture of surgical pads, foot cushioning and corrective devices,miscellaneous applicators, and the like, although the method may he usedfor other purposes, as will be apparent to one skilled in the art.

Various articles, and particularly surgical pads, foot cushioning,corrective and supporting devices, among others, are now commerciallymade with one or more layers of thermoplastic sheet or film, and one ormore layers of thermoplastic synthetic resin foam, with the layersjoined together by heat seal sea-ms made with suitable dies in anelectronic heat sealing press, wherein the dies are brought together anda high frequency electrical current sufiicient to fuse the plasticlayers is passed through the dies in an extremely short interval oftime. The articles so produced are far more durable, clean and sanitaryappearing than articles heretofore made for the same purpose, but ofdifferent materials cemented or stitched together. However, in themanufacture of such articles economy of production is an essential sincethe heat sealed article although made of far better materials must stillcompete on the open market with the old type of articles for the samepurpose made of more economic materials. In keeping with the necessaryeconomy of production, particularly with regard to articles of smallersizes, it is desirable to use multiple dies whereby a plurality offinished articles may be produced with a single operation of the dies.

Also, in keeping with economy it is at least highly desirable inconnection with smaller articles to provide both a heat seal and tearseal sea-m, so that in one operation of the dies not only is a heat sealseam established, but a tear line is provided so that waste stock may beremoved readily from around the finished article. In the past, this hasbeen extremely difficult to accomplish particularly where the finisheddevice is relatively thick in comparison with the overall area of thedevice. It has also been found to be practically impossible in the past,particularly with synthetic resin foams and sheets, to effect actualreshaping of an unsupported portion of the material, other than thatcontingent upon providing a bounding definition of the article, whileestablishing the heat seal seam. Further, in the past, all dies for thispurpose were capable of producing only one specific article, eithersingly or in multiples, but the dies could not readily be changed oraltered to provide an article of different specific character, anotherset of dies being necessary for the production of an article having anyalteration in shape. Still another objection to dies of this characterheretofore known re- United States Patent 0 sided in the difiicultyentailed in quickly and accurately positioning a plurality of layers ofmaterial, particularly if some of the layers were of different sizesthan the others, for multiple die operation.

With the foregoing in mind, it is an important object of the instantinvention to provide a method of using electronic heat sealing dies inconnection with synthetic resin foams, films, sheets and the like, inmultiple and in a single operation produce finished products ofrelatively great thickness compared with the area of the product andestablish all essential heat seal seams and all essential heat and tearseal seams in such operation.

Another object of this invention resides in the provision of a method ofusing heat sealing dies, highly suitable for acting upon synthetic resinfoams and sheets, in such a manner as to complete a finished product ina single operation, both establishing the essential heat and tear sealseams and also reshaping and providing what may be termed a permanentset in the reshaped material of the final product.

Another desideratum of this invention is the production of a method ofusing heat sealing dies to produce articles varying in thickness fromsheets of different areas, the dies being so constructed that precutblanks of stock material maybe quickly, easily, and accuratelypositioned to be acted upon by the dies.

Still a further feature of the invention is the provision of a new andnovel method of using electronic heat sealing (i in the making ofsurgical pads, cushioning and corrective devices, and similar articlesamong others, of heat sealable plastic material.

While some of the more salient features, characteristics and advantagesof the instant invention have been above pointed out, others will becomeapparent from the following disclosures, taken in conjunction with theaccompanying drawings, in whichi FIGURE 1 is a bottom plan view of anupper electrode die of :a type usable in practicing principles of theinstant invention;

FIGURE 2 is a top plan view of a lower electrode die of a type usable inpracticing principles of the instant invention and which cooperates withthe die of FIGURE 1;

FIGURE 3 is a plan view of an article made by operation of the dies ofFIGURES 1 and 2;

FIGURE 4 is a fragmentary enlarged vertical sectional view of thearticle itself, taken substantially as indicated by the line IVIV ofFIGURE 3, looking in the direction of the arrows;

FIGURE 5 is a transverse vertical sectional view through the lower die,taken substantially as indicated by the line V-V of FIGURE 2;

FIGURE 6 is a transverse vertical sectional view through the upper die,taken substantially as indicated by the line VI VI of FIGURE 1;

FIGURE 7 is a plan view of the lower die, showing the assemblage ofblanks thereon for the production of the article of FIGURES 3 and 4,with parts broken away to reveal parts therebeneath;

FIGURE 8 is a vertical sectional view showing the formation of anarticle like that of FIGURE 5 by action of the dies;

FIGURE 9 is a fragmentary plan view illustrating a finished product,removal of waste therefrom, and the completion step of the methodinvolved in making that product;

FIGURE 10 is a view similar in character to FIGURE 7 showing theassemblage of material on the lower die after the same has been adjustedfor the production of an article difiering specifically from that ofFIGURES 3 and 4, parts being broken away to reveal parts therebeneath;

FIGURE 11 is a view similar in character to FIGURE J 8, after the upperdie has been adjusted for the specifically different article, showingthe dies in operation forming the article; and

FIGURE 12 is an enlarged fragmentary vertical sectional view through thearticle made by the adjusted dies of FIGURES 10 and 11.

As shown on the drawings:

In the illustrated embodiment of dies suitable for the practice of thisinvention, referring particularly to FIG- URES l, 2, and 6, the upperdie comprises a base plate 1 of electrically conductive metal. Securedto this base plate is a plurality of die members, there being four shownin the illustrated instance, but it will be understood that this numbermay be varied as desired or to correspond to the capacity of theparticular heat sealing press available.

Each die member is preferably cup-shaped and comprises a bottom 2 and adepending skirt 3 integral therewith, the skirt in the illustratedinstance being substantially oval in contour. The die member may be madesatisfactorily of bronze, brass, or some other suitably electricallyconductive metal of sufficient durability. The die member may be securedto the base in any satisfactory manner such as by bolts 4, FIGURE 6, andit may be desirable to solder or copper braze the element to the base aswell to insure a complete electrical connection with the base. As alsoseen in FIGURE 6, the working edge of the skirt 3 slopes inwardly asindicated at 5 to provide a surrounding knife edge 6. This working edgearrangement provides both a heat and tear seal seam when the die isenergized while pressing into the material being heat sealed.

Within the skirt 3 of the die element is an auxiliary cup-shaped dieelement 7 which may be removably secured to the bottom 2 of the dieelement by a bolt and nut assembly 8, access being provided thereto byway of a suitable aperture 9 in the die base 1, as seen in FIG- URE 6.The auxiliary element 7 may have any suitable shape and size as desiredfor a particular finished product, and in the illustrated instance it isshown circular. The working edge of the skirt of the auxiliary element 7is flat as indicated at 10 so that this auxiliary element will provide aheat seal seam but no tear line. Where the finished product is to beprovided with a digit loop, each die element is preferably provided atthe desired location for the digit loop with a pair of opposedupstanding heat sealing strips 1111 bolted, or equivalently removablysecured to the inner face of the skirt 3 as indicated at 12, the upperends of these strips being flat so as to provide only a heat seal seambut no tear line, and terminating even with the inside edge of the slope5 on the skirt 3 well below the knife edge 6. Each die member ispreferably relieved inside the skirt 3 and around the auxiliary element7 by a resilient block 13 or stack of blocks as may be desired, whichrelief substance 13 may be sponge rubber or any equivalent material. Theprovision of the relief substance is to insure all resultant articlesbeing of uniform thickness.

The lower die, seen in FIGURES 2 and 5, need not be provided with anyoutline defining means, but may satisfactorily be in the nature of aflat plate 14 of electrically conductive material, preferably providedwith an upstanding guide flange 15 along the rear and one end edge. Atthe front side edge thereof, the plate is formed with a plurality ofoutwardly extending curvate projections 16, there being one for each ofthe die elements in the upper die. Each of these projections 16 isprovided with a depending flange 17 which may satisfactorily be ofsector shape. At the rear of the plate 14 spaced somewhat inwardly fromthe flange 15 are a pair of upstanding guide pins 18-18, any suitable ordesirable number being used.

The lower die is also provided with a recess 19 in proper location to besurrounded by the working edge of the auxiliary die element 7 when thedies are brought together. Each such recess is provided with a reliefblock 20 of sponge rubber or equivalent material, and seated freely onthe block 20 is a dome forming plug 21 which may satisfactorily beformed of thermosetting plastic or other suitable non-conductivematerial. This dome forming plug is relieved because while the pieces tobe joined together by the dies are stacked upon the lower die, more thanuseful height of the plug is needed to accommodate the stacked orsuperposed blanks and during operation of the dies as the blanks arecompressed, the plug 21 descends against the action of the relief block20 to the proper height for forming a dome in the finished article.

In FIGURES 3 and 4 I have illustrated the product made by the dies abovedescribed. In this instance the product is in the form of a surgical padhaving an elastic digit loop, the pad being shaped for the alleviationof a bunion or similar affliction of the foot, and it will of course beunderstood that made in a smaller size, the pad will be effective forthe alleviation of a tailors bunion. The particular pad illustrated isone desirable for use where there may be exudation from the affliction,or where the affliction is sensitive to frictional contact with evenlight wearing apparel such as a stocking.

The pad comprises a lower layer 22 of heat sealable plastic film such asa vinyl or acetate film, a lower layer 23 of heat sealable foam such aspolyvinyl chloride foam, polyurethane foam, or equivalent material, apartial upper layer 24 of the same foam, and a cover layer 25 preferablyof transparent plastic film. Extending inside one end of the pad so asto overlie the bottom film layer 22 is an elastic digit loop 26 whichmay satisfactorily be formed of commonly known woven fabric elasticribbon having its ends secured together in any suitable manner such asby stitching or stapling to form the loop, the secured ends being insidethe pad.

These layers are joined together by a fine line heat and tear seal seam27 defining the bounding edge of the pad. The lower film layer 22 isapertured as indicated at 28, the lower foam layer is also apertured inthe same region, the upper foam layer is cut away, while the top filmlayer 24 remains intact. A heat seal seam 29 joins at least the films 22and 25, and possibly the adjacent edge of the foam layers surrounding adome 30 formed in the top film 25 at the time the heat seal seams areestablished to provide a smooth slick covering over the afflictionitself.

In making pads of the character shown in FIGURES 3 and 4, the upper faceof the lower die 14 is first covered with a blank of material 31 tofunction as a dielectric bufier, and this sheet may satisfactorily bemade of polytetrafluoroethylene. This sheet is merely for the protectionof the dies and is immune to the heat sealing operation. The sheet isapertured to fit over the guide pins 18-18 and over each of the domemolding plugs 21, and this sheet may remain on the die indefinitelythrough numerous operations. The layers that make up the finishedarticle are stacked on top of the buffer sheet 31.

It will be understood that the layers of material making up the finishedarticle are in the form of precut blanks of a size to fit the upper faceof the lower die. Each of these blanks is provided with apertures forengagement over the guide pins 18--18 and also, with one exception,provided with apertures to receive the upwardly projecting dome plug 21.Each of the blanks, with a different exception, is also shaped toprovide curvate forwardly extending projections corresponding in sizeand location with the projection 16 on the lower die.

First upon the buffer sheet 31 is a blank 22a which ultimately forms thelower film 22 in the finished article. The apertures for the domemolding plugs 21 in thisfilm 22a are of a size to just intimately fitover the dome plug. Next the digit loop 26 is placed in position overtheprojecting portion 16 of the die, as seen in FIGURES 7 and 8, and thedepending sector flange 17 maintains this loop in position againstsliding off the projection. The loop overlies the blank 22a. A blank 23aof foam material overlies the film blank 22a and the digit loop 26. Thisblank 23a is provided with an aperture 32 for each dome plug 21 that isnoticeably larger than the plug so as to leave a space entirely aroundthe plug as best seen in FIGURE 7. On the foam blank 23a a partial foamblank 24a is positioned, this blank having a circular notch 33 thereinfor each of the dome plugs 21, the notch being of the same diameter asthe aperture in the first foam blank 23a. Finally the top film blank 25ais placed in position, this film having no aperture therein except thosefor the guide pins 18-18, and this film completely overlies each of thedome plugs 21.

With all of the blanks so positioned, the upper die is next brought downupon the material on the lower die as shown in FIGURE 8 under pressure,and when the respective blanks have been compressed to substantially thedegree shown in FIGURE 8, a charge of high frequency electric-a1 currentis passed between the dies, and a very few seconds is sufiicient forthat current to effect the heat seal seam 29 occurring around the domemolding plug 21 in spaced relationship thereto and also provide the heatand tear seal seam 27 defining the bounding edge of the device. The diesare shown in their position at the completion of an operation in FIGURE8, and it will be noted that the relief block 20 for each dome moldingplug 21 is somewhat compressed below its original height seen in FIGURE5, and the relief block 13 in the upper die has also been compressed insomewhat of a dome shape. This relief block in the upper die insures allof the resultant pads as being of the same thickness, while the reliefblock 20 permits the dome forming plug to extend upwardly sufiicientlyfor positioning of the blanks, and then yield until it is at the properheight to form the dome 30 in the upper film 25. The actual height ofthe finished dome may be controlled or varied v the use of a shorter orlonger dome forming plug '21. In forming the dome, as the upper die ispressed upon the lower die, the filrn of the blank 25a is stretched coldand heat sealed at its lower edge at least to the lower film 22. Thus apermanent deformation is established in the upper film and it willretain its dome shape throughout the life of the pad.

During the pressing of the blanks together the air in the foam layers 23and 24 is squeezed out to a material extent prior to the establishmentof the heat seal seams. The finished pad is therefore flatter thandesired by virtue of the partial vacuum inside it. Therefore it isdesirable, as a final step in the method, to provide either the upper orlower film 22 or 25 with a minute perforation such as by a needle 34 asseen in FIGURE 9. This permits air to enter inside the casing formed bythe two films and the foam layers expand as much as possible in theconfined space, restoring the pad to the desired thickness and renderingit highly resilient and comforatable without any danger of the foammigrating laterally under pressure points.

The two strips 11-11 in the upper die member also effect heat sealingfor their widths, which short seams as indicated at 3535 in FIGURE 9 aresubstantial enlargements of the heat and tear seal seam 27 formed by theknife edge 6 of the upper die as well as the slop-. ing portion 5thereadjacent. In effect, the bounding heat seal seam is widened at thelocation of the strips 1111 directly over the digit loop. At the timethe heat seal seam is formed, aided by the location of the strips 1111,the thermoplastic material of the layers is melted into the elasticdigit loop. The tear seal, effected by the sharp edge 6, is notdisturbed by way of the attachment of the band, and as indicated at 36in FIGURE 9 waste stock may readily be torn from the finished paddirectly over the band as well as elsewhere. The band is not severed bythe edge 6 of the top die, and this is controlled by the distance oftravel of the top die. As to the particular showing in FIGURE 9, thewaste stock would not be broken, as appears for illustrative purposesonly, but the entire waste would be removed from around the finished padin one piece.

It will be noted that the pad is formed with a single operation of thedies, and a portion of the material making up the pad is cold stretchedand given a permanent set to provide the dome 30 which overlies theafiliction.

Now, with reference to FIGURES 10, 11 and 12, I have illustrated how thedies may be rearranged to provide a pad without a dome, but insteadhaving an aperture entirely through the pad where the dome 30 waspreviously. In this instance, the same main dies are used, but the guidepins 1818 and the dome forming plugs 21 have been removed from the lowerdie. The upper die has been arranged by eliminating the auxiliary heatsealing die element 7 and substituting therefor a similarly shaped dieelement 37 having an inner knife edge 38, FIGURE 11, of the samecharacter as the knife edge 6 on the skirt 3 of the main die elementdefining the outline of the finished article. This substitution iseasily accomplished by releasing the bolt nut assembly 8, removing theelement 7, substituting the element 37, and tightening the bolt nutassembly, for each die element embodied in the upper die.

In this instance, since there is to be no cold stretching and deformingof any of the laminated sheets, as when the dome was provided in thefirst described embodiment, the blanks do not have to be apertured tofit over the pins 18-18, and the only preforming necessary is to cut theblanks in plain rectangular sheets of a size to fit over the lower die.These blanks then may all be positioned by seating them snugly againstthe upstanding flange 15 on the lower die, as seen in FIGURE 10.

Since the die element 37 will remove a circle of material larger thanthe recess 19 for the dome shaping plug 21 in the lower die, the samedielectric material 31 may be utilized, or an unapertured sheet ofdielectric material 39, FIGURE 10, may be laid over the lower die 14. Ontop of the dielectric sheet, a lower film 22b, is placed, and in theevent the toe or digit loop 26 is to be utilized, this lower film 22bwill be precut to fit individually over each of the projections 16 onthe lower die. In the event the digit loop is not utilized, and the padis to be completed without it, the film blank 22b may satisfactorily berectangular. On the film blank 22b a foam blank 23b is positioned, andthen a foam blank 24b of lesser width is placed on top of the largerfoam blank, and finally the top film blank 25b is placed. After theblanks have all been positioned, the dies are brought together in themanner seen in FIGURE 11, and upon pressure of the upper die on thelower and the charge of high frequency electrical current therethrough,not only is the heat seal seam 27 defining the outline of the padestablished, but simultaneously therewith an inside heat and tear sealseam 40 is established by the die element 37, so that in the resultantpad the heat seal seam 40 defines an open aperture, after the removal ofthe waste as above described.

It will be noted that with the use of the present dies, in the methodherein set forth, a pad having a set domelike formation to overlie theafiliction may be provided, pads with or without digit loops may beprovided, a pad having a complete aperture for the reception of theaffiiction may be provided, the dome shaped portion or the aperturethrough the device may have substantially any desired shape, and all ofthe pads are uniform in thickness regardless of the fact that each padis thicker in one portion than in another. After the operation of thedies it is a simple expedient to put a minute perforation in each of thepads to cause the foam material to swell and render the pad of the rightsize and resiliency. The dies in the practice of the method are bothextremely economical and quite satisfactory for commercial production ina competitive field. Any changes in the specific construction of the padis accomplished by a simple adjustment of the die member requiring aminimum of time and labor.

It will be understood that modifications and variations 'may be effectedwithout departing from the scope of the novel concepts of the presentinvention.

I claim as my invention: 1. The method of making a cushioning padincluding the steps of superposing layers of fusible material havingaligned apertures therein, covering said layers with a top imperforatelayer, heat and tear sealing said layers in a seam defining the boundingedge of the pad around said apertures, and simultaneously deforming saidtop layer into a dome over said apertures. 2. The method of making acushioning pad including the steps of superimposing layers of fusiblematerial having aligned apertures therein, covering said layers with atop imperforate layer, heat and tear sealing said layers in a seamdefining the bounding edge of the pad around said apertures, and joiningall said layers by a heat seal seam around said apertures, and deformingsaid top layer into a dome over said aper- =tures. 3. The method ofmaking an article from heat scalable material, including the steps ofsuperposing a cover layer and a cushion layer having aligned openingstherein, placing an imperforate top cover layer on said cushion layer,compressing and heat sealing all said layers together by a heat sealseam defining the outline of the article, and providing a deformation insaid top layer adjacent the openings in the other layers. 4. The methodof making an article from heat sealable material, including the steps ofsuperposing a cover layer and a cushion layer having aligned openingstherein,

placing an imperforate top cover layer on said cushion layer,

compressing and heat sealing all said layers together by a heat sealseam defining the outline of the article,

joining said layers by a heat seal seam around said openings, and

simultaneously forming a dome in said cover layer over said openings.

5. The method of making an article from fusible materials including thesteps of superposing a thin cover layer of thermoplastic material and athicker foam cushion layer having aligned openings therein,

placing an imperforate top cover layer over said cushion layer,

contemporaneously compressing said foam layer and joining said coverlayers by a heat seal seam around said openings and a heat seal seamdefining the outline of the article,

simultaneously providing a permanent deformation in the top cover layerover said openings, and

thereafter puncturing one of said cover layers to admit air forexpansion to said foam layer.

References Cited by the Examiner UNITED STATES PATENTS 2,750,606 6/1956Freedlander et a1 5-337 2,803,023 8/1957 Rosenberg et a1 5-337 2,878,1533/1959 Hacklander 264-248 2,898,634 8/1959 Alderfer 264-47 2,917,84212/1959 Scholl 36-71 3,083,392 4/1963 Sewell 15-118 EARL M. BERGERT,Primary Examiner.

DOUGLAS J. DRUMMOND, Examiner.

1. THE METHOD OF MAKING A CUSHIONING PAID INCLUDING THE STEPS OFSUPERPOSING LAYERS OF FUSIBLE MATERIAL HAVING ALIGNED APERTURES THEREIN,COVERING SAID LAYERS WITH A TOP IMPERFORATE LAYER, HEAT AND TEAR SEALINGSAID LAYERS IN A SEAM DEFINING THE BOUNDING EDGE OF THE PAD AROUND SAIDAPERTURES, AND SIMULTANEOUSLY DEFORMING SAID TOP INTO A DOME OVER SAIDAPERTURES.